Polyesters with improved dyeability

ABSTRACT

COMPOUNDS USEFUL FOR THE PRODUCTION OF CATIONIC DYEABLE POLYESTERS, HAVING THE FROMULA:   BIS((4-(M-O3S-)PHENYL)-O-CH2-)C(-CH2-OH)2   WHEREIN M IS SELECTED THE GROUP CONSISTING OF ALKALI METALS AND AMMONIUM.

United States Patent 3,812,178 POLYESTERS WITH IMPROVED DYEABILITY GeneClyde Weedon, Richmond, Va., assignor to Allied Chemical Corporation,New York, NY. No Drawing. Original application Nov. 16, 1971, Ser. No.199,353, now Patent No. 3,753,949, dated Aug. 21, 1973. Divided and thisapplication Apr. 30, 1973, Ser.

Int. Cl. C07c 143/42 US. Cl. 260-512 R 1 Claim ABSTRACT OF THEDISCLOSURE Compounds useful for the production of cationic dyeablelinear polyesters, having the formula:

HOCHa7CCH: OH

CH3 CH onvr soar wherein M is selected from the group consisting ofalkali metals and ammonium.

This is a division of application Ser. No. 199,353, filed Nov. 16, 1971,now Pat. No. 3,753,949, granted Aug. 21,

BACKGROUND OF THE INVENTION This invention relates to new polyesterpolymers. The invention also relates to fibers, filaments, yarns, films,and other structures of said polymers, which have an allinity fordyestuffs.

Linear polyesters are well known and are readily prepared by thereaction of dihydric alcohols or their functional derivatives withdibasic carboxylic acids and their ester forming derivatives. Thus, forexample, polyethylene terephthalate may be produced either by the esterinterchange reaction between dimethyl terephthalate and ethylene glycolor the so-called direct esterification methof as initially enunciated inUS. Pat. 2,465,310 and more recently in US. Pats. 3,024,220; 3,050,533and 3,050,548.

Although the processes for preparing linear polyesters that are usefulin making films and fibers have been relatively successful, manyproblems remain, particularly in dyeing the fiber and products madetherefrom. For example, when various dye ingredients, such asphosphonates, sulfones and various sulfonates are used, they adverselyeffect the final physical properties of the product, thus making suchproducts unsuitable in the market place. Some previous elforts by thoseskilled in the art to over come polyester dyeing problems areillustrated in US. Pats. 3,164,566; 3,164,567 and 3,164,570, and suchpatents are hereby incorporated by reference. Therefore, an improveddyeable linear polyester suitable for use in preparing fibers and filmsand allowing greater end uses for these products as well as the processfor preparing said polyester would make a substantial contribution tothis art.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object ofthe present invention to provide a modified linear polyester suitablefor use in making films and filaments. Another object of this inventionis to provide a new linear polyethylene terephthalate polymer suitablefor use in making films and filaments that are readily dyeable byordinary dyeing techniques while at the same time retaining excellentheat stability, dimensional stability and strength. A further object ofthis invention is to provide an improved process for preparing a newlinear polyester polymer suitable for use in making films and filamentsof improved dye receptivity. Still another object of the presentinvention is to provide an improved process for preparing a cationicdyeable modified polyethylene terephthalate polymer suitable for use inmaking films and filaments.

These and other objects and advantages which will be obvious hereinafterare achieved by the present invention which is set forth in thefollowing description wherein parts and percentages are by Weight.

The modified linear polyesters of this invention are preparedessentially from an aromatic dicarboxylic acid, or a dialkyl esterthereof, with a diol, desirably an aliphatic glycol containing from 2 to10 carbon atoms, and a small amount of a sulfonate compound of thegeneral formula:

HOCHz-C-CHzOH C 3 CH3 6 b l S 0 M 03M wherein M is selected from thegroup consisting of lithium, sodium, potassium, rubidium, cesium, andammonium. A preferred class of such polyesters is prepared fromterephthalic acid, or an ester forming derivative thereof, and analiphatic glycol wherein the aliphatic glycol is present during thereaction in amounts ranging from 1.1 to 2.0 moles of aliphatic glycolper mol of dicarboxylic acid in the presence of 0.01 to 15 mole percent,preferably 0.1 to 5.0 mole percent, based on the aliphatic glycol, of asulfonate compound of the formula:

s 0 M 03M wherein M is preferably selected from the group consisting ofsodium and potassium.

The di-(p-sulfophenoxy)-neopentyl glycol compounds of the presentinvention are members of a class of novel compounds that are readilyprepared from dibromoneopentyl glycol. Thus, for example, the compoundrepresented by the formula:

HOCHr- C-CHI OH CH3 CH3 S'OaNa S03Na can he prepared by refluxing anaqueous sodium hydroxide solution of phenol sulfonic acid, sodium salt,with dibromoneopentyl glycol. The instant sulfonated compounds areextremely heat stable, colorless, and capable of being used inboth'dimethyl terephthalate and terephthalic acid polymerizationprocesses for production of polyesters. Moreover, the novel sulfonateclcompounds are relatively inexpensive.

Suitable diols for the production of the polyesters of this inventionare the aliphatic diols represented by the general formula HO(CH OHwherein n is an integer of from 2 to 10, such as ethylene glycol,trlmethylene glycol, hexamethylene glycol, decamethylene glycol, and thelike. Also suitable are 1,4-cyclohexanedimethanol, p-xylylene glycol,and the like. It is known that any glycol of an aliphatic nature,whether or not it contains aromatic nuclei, can be used in theproduction of linear polyesters. Thus, the term aliphatic glycolsincludes all those glycols of an aliphatic nature which are known to theart to be suitable.

The preferred dicarboxylic acid compounds for the production of thepolyesters of this invention are the aromatic dicarboxylic acids, whichare well known to those skilled in the art. The most preferreddicarboxylic acid is terephthalic acid and the dialkyl esters thereof,such as dimethyl terephthalate and similar esters in which the alkylgroups preferably contain from 1 to 5 carbon atoms.

It will be understood that the linear polyesters of this inventioncontain the recurring units represented by the following generalformulae:

from the aliphatic glycols as defined above, wherein the recurring unitsare attached to one another so as to form an ester link The basic orcationic dye useful in this invention is a colored organic substancesuch as those containing sulfonium, oxonium, or quaternary ammoniumfunctional groups.

In producing the dyeable linear polyesters of this invention, thecalculated amounts of aryl dicarboxylic acid compound, glycol,sulfonated compound modifier, and catalyst are charged to a reactor andheated at a temperature of: from about 150 C. to about 270 C. in aninert atmosphere to etfect the initial interchange reaction. Then excessglycol is removed by heating to about 280 C. at reduced pressure in aninert atmosphere. Thereafter, the polycondensation is carried out atfrom about 260 C. to about 300 C. at reduced pressures of from about 0.1mm. to about mm. of mercury, also in an inert atmosphere. The totalreaction period can be from about One to about fifteen hours, accordingto the catalyst employed, the temperature, the pressure, the startingmonomers, and the viscosity desired for the polyesters, as is known inthe art.

The monomers are normally reacted in contact with a suitable catalyst inorder to shorten the reaction period. Any of the well-knownpolyesterification catalysts can be used such as antimony oxide, zincacetate, manganese acetate, cobaltous acetate, zinc succinate, and thelike. The concentration of the catalyst can be varied from about 0.001percent to about 1 percent by weight of the total amount of dicarboxylicacid compounds charged.

Unexpectedly, the instant sulfonated compound modifiers have sufiicientstability, both chemically and thermally, to withstand thepolycondensation conditions in the presence of other reactants, as wellas the high temperatures necessary for spinning the polyesters. It wasalso surprising that the dye receptivity in basic dyes of the fiberforming polyesters prepared in accordance with this invention isincreased substantially, namely, up to ten fold over that of fiberforming polyesters prepared in a way other than in accordance with thisinvention. Further, the modified polyesters of this invention showed nodisadvantage in physical properties over unmodified polyester fibers.

DESCRIPTION OF THE PREFERRED EMBODIMENT In order to demonstrate theinvention, the following examples are given:

Example 1 This example demonstrates preparation of(di-sodiosulfophenoxy)neopentyl glycol, a preferred polyester modifierof the present invention. About 10 grams of sodium hydroxide wasdissolved in 500 grams of water and the solution was heated to refluxtemperature. Next, 58 grams of phenol sulfonic acid (para), sodium salt(hydrate, 2H O), was dissolved in the solution. Then, 32.8 grams ofdibromoneopentyl glycol was added and the reaction mixture was refluxedfor 3 hours. No precipitate was formed when the reaction mixture wascooled to room temperature but the product crystallized on cooling themixture in an ice bath. The solid product was separated by filtrationand dried in a vacuum oven. This material weighed 29.6 grams. Theprecipitate was subsequently extracted with ethanol in a Soxhletextractor. After drying the alcoholic extract, 23.4 g. of product wasrecovered. Sulfur analysis of the extracted product indi cated that thedesired sulfonate was obtained having the following structure.

H O CH:- CCH, OH

CH, CH;

I soon; OsNB The product compound was colorless and extremely heatstable. That is, the compound was stable at temperatures normally usedin production of polyesters. Melting point was 408 C. Example 2 showsthat the novel compound is readily incorporated into polyesters and thatthe resulting polyesters are heat stable and have improved dyeability.

The corresponding potassium sulfonate compound is prepared in a similarmanner by substituting equivalent amounts of potassium hydroxide andphenol sulfonic acid (para), potassium salt, in the above procedure.

Example 2 A glass reactor was charged with a mixture of 739.3 grams ofethylene glycol, 1164.0 grams of dimethylterephthalate, 35.0 grams ofdi(sodiosulfophenoxy)neopentyl glycol (prepared in accordance withExample 1), and 0.41 grams of manganese acetate. The mixture was thenflushed with nitrogen and was then heated to 200 C. over a five hourperiod at atmospheric pressure to produce an ester interchange reaction.Methanol distilled off continuously during the ester interchangereaction and the distillation was practically completed when thetemperature reached 200 C. The reaction mass was then cooled to roomtemperature and the reactor was opened. Next, 2.28 grams of antimonytristallate and 3.25 grams of trinonylphenylphosphite were added to thereaction mass. The reactor was closed and the reaction mass was againflushed with nitrogen and was then heated to 275 C. over a one hourperiod to produce a polymerization reaction.

Heating was continued at 275 C. for an additional five hours underincreasing vacuum to a final vacuum of 0.08 mm. Hg. Nitrogen was thenadmitted to the reactor and a small pressure was maintained while thepolyester copolymer was extruded from the reactor in the form of apolymer ribbon. The polyester copolymer ribbon was subsequently cooledand pelletized using a Wiley Mill. The polyester copolymer was a clearsolid having a reduced viscosity of about 0.73 in orthochlorophenol anda melting point of about 246 C. The reduced viscosity was calculatedusing the following equation:

"red ("r /C where:

n =reduced viscosity C=concentration of dissolved polymer in grams/ 100ml.

n =relative viscosity=t /t (flowtime polymer solution/ fiowtimesolvent).

The polyester copolymer pellets were dyeable with basic dyestufis to agood shade.

This polyester copolymer was designated polymer A.

Example 3 For comparative purposes, a polymer was prepared in a mannersimilar to polymer A of Example 2 except that nodi(sodiosulfophenoxy)neopentyl glycol was added to the initialingredients. The resulting polymer was designated polymer B. Polymer Bhad a melting point of 254 C. and a reduced viscosity of about 0.72 inorthochlorophenol.

Example 4 Polymers A and B of Example 2 and Example 3 were dried in avacuum oven at 150 C. for 16 hours and spun on a one-inch extruder. Theextrusion and spin block temperatures were about 295 C. Polymers A and Bwere drawn at a draw ratio of 4.0 to 1 into 70- denier, 16-filamentyarns, which were knitted into Sleeve A and Sleeve B, respectively. Aswatch from each sleeve was cationically dyed with Nabor Blue B (0.1.Basic Blue 21) according to the following procedure:

Each fabric sample was dyed in an aqueous dye bath containing:

10.0% (on weight of fabric) Nabor Blue B (Cl. Basic Blue 21) 1.6% (onweight of fabric) glacial acetic acid 0.6% (on weight of fabric) sodiumacetate.

The Weight of dye bath to fabric was maintained at 30:1. The fabricsample was immersed in the aqueous dye bath at C. in an autoclave. Thetemperature was raised to C. at the rate of three degrees per minute andwas maintained at 140 C. for three hours. The fabric sample was thenrinsed in warm water and dried.

The dye uptake of the samples from Sleeve A and Sleeve B was measured bydissolving 0.1 gram of each dyed sleeve in a mixture of 1.5 ml. ofmonochlorobenzene and 1.5 ml. of melted phenol. The resulting solutionwas diluted with acetone to volume of 25 ml. The solution was thencentrifuged to separate precipitated polymer, and the light absorbancy(at 550 nanometers) of the dissolved dye solution was measured. Sleeve A(containing sulfonate additive) had an absorbency per unit weight ratioof 1.2x 10 Sleeve B (without sulfonate additive) had an absorbency perunit weight ratio of only 0.5 x10- Visually, Sleeve A was observed todye to a much greater extent than Sleeve B.

I claim:

1. A sulfonate compound of the formula:

HOCHz- C-CH; 0H

wherein M is selected from the group consisting of lithium, sodium,potassium, rubidium, and ammonium.

References Cited UNITED STATES PATENTS 2,335,136 11/1943 Thuau 260-507LEON ZITVER, Primary Examiner N. CHAN, Assistant Examiner US. Cl. X.R.260-33.4 P

